A cooling fan is widely used in an engine cooling system for a vehicle. The cooling fan is typically driven by a direct current (DC) brush motor. It is desired to reduce the axial dimension of the motor to provide more space for other components of the engine, without reducing the lifespan of the motor.
U.S. Pat. No. 6,737,774B discloses a cooling fan motor with a flat structure. The motor has a housing with a magnet attached to an inner surface there of, an end cap closing one end of the housing, a rotor core fixed to a shaft, a rotor winding held at an outer circumference of the rotor core, and brushes for supplying power from a battery to the rotor winding. A commutator is partly arranged in a space defined by the shaft, the rotor core and an inner surface of the rotor winding. The brushes are axially spaced from the winding and fixed to the end cap to make sliding contact with segments of the commutator.
U.S. Pat. No. 5,434,463 discloses a motor with a flat structure in which the commutator is disposed in a recess that extends further into the body of the rotor core. However, the manufacture of this motor is relatively complex with the rotor core being formed from a number of different laminations being stacked together.